Middle Palaeolithic Human occupations, cultural behaviours and demographic dynamics during MIS 5a to late 3 in the Bawa Yawan Rockshelter, Kermanshah, West-Central Zagros Mountains

Despite many years of research into the Middle Palaeolithic in the Zagros Mountains, numerous aspects of this period have not yet been sufficiently investigated. The topics of Middle Palaeolithic's cultural behavioures, temporal changes, chronology, and the nature of the transition from the Middle to the Upper Palaeolithic in this region have led to various opinions and debates. Three seasons of archaeological excavations at the Bawa Yawan Rockshelter, located in the west-central Zagros, have uncovered a continuous stratigraphic sequence spanning from the Middle to the Epipalaeolithic periods. The site yielded in situ Neanderthal remains along with a substantial assemblage of lithic and faunal materials. The findings suggest a relatively homogeneous Mousterian lithic trajectory throughout the Middle Palaeolithic period, with slight variations likely reflecting differences in hunting strategies. Furthermore, these data indicate a cyclical pattern in population size dynamics, likely in response to climatic variations during the late Marine Isotope Stage 5a to the middle of 3. The data reveal that the Neanderthals, after a relatively substantial period in late MIS 5, experienced a demographic stagnation in MIS 4. The same data shows that their population grew significantly just before extinction around 45,000 to 40,000 years ago. This article represents a step forward in understanding human evolution during the Late Pleistocene in the Zagros Mountains, within the territory of Southwestern Asia. • Three excavation seasons at Bawa Yawan Rockshelter reveal continuous occupation from the Middle to Epipalaeolithic periods. • In situ Neanderthal remains and a rich assemblage of lithic and faunal materials were uncovered. • Mousterian tool technology remained relatively stable throughout the Middle Palaeolithic, with minor environmental adaptations. • Population dynamics show cyclical changes linked to climatic fluctuations from late MIS 5a to mid MIS 3. • Evidence suggests that Neanderthals experienced demographic stagnation during MIS 4, followed by population growth before their extinction between approximately 45 and 40 kyr in the western Zagros Mountains.